Conventional spark plugs are formed with a separate hexagonal nut, a metal body which surrounds and supports the central electrode, and a ceramic insulator which surrounds the central electrode rod and electrically insulates the rod from the metal of the hexagonal nut and threads. The ground electrode is normally welded to a conventional outer metal shell which is exteriorally threaded.
While this type of spark plug works well, the cost is substantial due to the component parts used and the manufacture and construction thereof.
The present invention reduces the costs of the material needed and simplifies the manufacture of the plug by reducing it to a single step injection molding process, as subsequently explained.